monopsony
noun
ECONOMICS uk/məˈnɒpsəni/ us [ U ]
a situation in a market in which there is only one buyer for goods or services offered by several sellers:
Since most of the biggest marketplaces are run by buyers, they tend to risk monopsony.
[ C ]
a buyer who is the only one in a market in which the goods or services are offered by several sellers:
People have accused the big wine buyer of being a monopsony.
monopsonist
noun [ C ]
For many years the steel industry has acted as a monopsonist.